Alternating-current motor.



V. A. FYNN. ALTERNATING CURRENT MOTOR.

APPLICATION FILED MAY 23, 1911,

Patented FM), 3. i914.

VALRE ALFRED FYNN, 0F LONDON, ENGLAND.

Specification of Letters Patent.

' Application filed May 23, 19H..

i ALTRNATING-CURRENT MOTOR.

Patented Feb. 3,19ji4. serial Nn. eases?.

'To all 'whom it may conce/fn Be it known that I, VALRE ALFRED FYNN, a subject of the King of England, residing at London, England, have invented a certain new and useful Alternating-Current Motor, of which the following is such a full, clear, and exact description as will enable any one skilled in the art to which it appertains to make and use the same, reference be* ing had to theV accompanying d 'n.wings, forming part of this specification.

My invention relates to single. phase alternating current commutatcr nmtors et the induction type and more particul to motors having 'Working and exciting brushes which start as self-excited series induction motore and operate as such, or are converted `vol.ts per turn impressed into motors with a shunt characteristic after a, certain speed has been reached.I

It has been proposed, in order to vary the starting torque, or the speed torque curve of the type of series motors above referred to, to suitably displace all the brushes, or the exciting brushes only,or to interpose an adjustable ratio series transformer between theworking and the exciting brushes. It is mechanically objectionable, and sometimes impossible, to move the brushes and it is cr;- pensive to provide` an adjustable series transformer. It is the object of my invention to pron duce a single phase self-excited induction motor the starting torque, the torque curve andthe power factor c' which can be easily adjusted to suit any given con ditions and Wl'iich can be easilyiccnverted into a machine with a shunt lcharacteristic When desired without moving'any brushes or using any transformers external to the motor.

My invention Will be better understood by reference to the following description taken in connection with the aconipanying diagrammatic drawings, in which-F Figure 1 shows a two-pole form of my imroved motor 'arranged to be partly con trolledfrom a distance, and Figs. 2 and 8 show the circuits established by the 22, and 25 respectively.

The stator carries a main inducing winding 8 connected to the mains l, 2, by Way of The position of the regulating resistance 3.

the

the'movable Contact il on 3 determines switches l The rotoris provided with a commuted .Winding 9 on which rest the working brushes l0, ll and the exciting'brushes i8. he I I axially with 8, the latter-arc preferably displaced by electrical degrees from the former as shown. *y

The two stator eld windings displaced .by 90 electrical. degrees from the main inducing winding. Each stator field winding is included between one set ot working and one set of excitino' brushes, The magnitude and directionv oit' the inagnetiaation produced by each stator field winding is adliustable at 1S and l) respectively. 'rfb/e direction ol rotation depends on whetiie" the working brush 10 is con uccted to the exciting Ybrush and the working brush l to the exciting;` brush 'i3 or whe-tl l0 is connected to ifi and ll to )le shown 'these connections l2. In the examil are controlled by the tvo way switch 5, wnich may be plated at any desired distance from the motor. Switch 5 controls the solenoids 2O 2l and the latter control the switch blades 23, Qfi a nd 2G, 27by means of which the interconnections between working and exciting brushes are made. ln the ligure switch stands on point 6,---thc solenoid 2l is therefore energized and attracts the core and causes the blade Q6 to connect points 3S, also the blade il? to couriect points Slt and The rotor connec4 tions are 'gheretorc as follows: from the working brush l0 to contact 35, blade 2T. contact Re, movable contact i9, through part of the stat( winding .la to poiuti'l the coiumuted wind? g the exciting brush lil, the Vpoint 'itt uudway on the stator field winding i5, through part of that winding to the. movable contact i8, to point 3S, blade QG, point 32, working brush l l, to tln` cornmuted ywinding` 9 and back to brush lil. ln other words, the working brush l() is connected to the exciting' brush 'lf2 by way ot the stator field winding Il and the working brush il is connected to the exciting brush i3 by way of the stator lielcl winding l5. ln order to reverse the direction of rotation ot the motor, switch 5 is moved 'from point G to point T The switch i then disengage 'from the contacts tt?, Elfi and 34-, respectively while the contacts Q9 `and 3l are bridged b'y the blades lil and Vvlhoncvcr the motor is in operation and former are preterablyp :iced coi4, l5 are blades 26 and 27 it is desired to convert same, into e machine with a shunt characteristic I short-circuit the 'working brushes 1G, ll by means of the switch lIflie resistance f3 is preferably used at starting only, but can be used for adjusting the speed 'torque curve of the machine, as long as the latter operates with a series characteristic., or for adjustingthe maxi,- inum output oi the machine as long as the latter operates with a shunt characteristic. The speed torque 'curve of the motor operating with a series charucteristic and its power factor at a given speed can, however, be much more economically adjusted bysuitably adjusting the magnitude and the direction oif'the magnetization produced by one or more of the stator iicld windings. This is achieved. in the figure by suitably displacing contacts 1S or 19 or both. l'llhen the magnetization due to the stator field Wind# ings opposes that due to the rotor along the same airis, then the motor will be able, when running with a series characteristic, to develop a greater torque at a given speed and vice versa. fr high power factor will also be reached under these conditions at a lower the, motor has been converted into a machine with a shunt characteristic by closing switch 8G, its speed can be adjusted hy varying the magnitude or direction of the magnetization.produced by one or more of the stator field windings. rlhe number of turns and the direction or magnetization produced by the stator field windings an be adjusted once for all and any necessary ad* ditioiial regulation an be carried out iii some other Way, for instance, by ineaiis'olz the resistance 3.

Although a tivdpole motor hasbeeii described it will be understood that the inveriliioii is applicable to machines :'With any number of pole airs A* Having Yfully described my` iiirein'ion, what claim as new and desire. to secure by lietters latent oit the Uniter States, is: I

l. ln an alternating current motor, the

combination willi an iiuluciire` member proi `vided with a main inducing' uindiirr` of an induced member provided with a couuuutcd Winding, a working` brush located in thc axis oit' the main inducing winding`r two cxciting` brushes each displaced therefrom, and an auxiliary winding on the induced memher displaced from the main Winding? the working brush being' connected to one or (he other only o'll the exciting brushes and vided with a main inducing winding' incase? winding, two Working brushes each in the axis of the main inducing;` winding() an ci;- citing brush displaced therefrom, and an auxiliary Winding on the induced member displaced from the main winding, the exciting brush being 'connected to one or the other Aonly ci? the working brushes and said con.v

nection including the auxiliary winding.

3. lin an alternating current motor9 the combination with an inducing member provided with a. main inducing Windingr and two auxiliary windings displaced therefrom or" an induced member provided with a coni muteiY winding, working brushes coaxial `with the mam inducing Winding, exciting brushes displaced from the working l'irushcs, and means for establishing two circuits cach, including one auxiliary Winding, one ot the working brushes and one of the exciting,` brushes,

in an alternating current motor, the combination with an inducing member provided With a main inducing Winding; and tivo auxiliary windings displaced therefrom by electrical degrees, of an induced member provided 4with acommuted windiit; Working rushes coaxial with the-main in ducing winding, exciting brushes displaced by OO electrical degrees from the Workingy brushes7 and means for establishing two circuits each including one auxiliary winding., one of the working brushes and one of the excitiufer brushes.

5. ln an alternating current motor, the combination with an inducing member proand two auxiliary windings displaced i'xheie, 5 of aninduced member provided with a conn united ivindingy working brushes cca al with the main inducingwinding, exci brushes displaced by' 90 electrical degrees from the workingr orushes, and uji/Jans for establishing tu'ocii'cuits each including; une auxiliary winding', one of the wei-laine; brushes and one oilhe exciting brushes.

l'n testimony whereof, l have hereunto set 'i my hand and aliixcd my seal in the presence ot the two subscribing witnesses.

vimini iiiiiiuai rim. [n lVilnesses:

ll". ALEXANDER, lCLizAinrrii Banni. 

